Ownership of land and property is based on title - documents (e.g. deeds) that are bearable = who holds the documents also 'owns' the property, even if temporarily, until a debt (i.e. a mortgage) is paid in full.

If the debt part of the title has been 'extracted' and resold to multiple investors, and further bets on that debt have been resold, it then becomes impossible to decide who owns that title.

If the land or property market is expanding, and the mortgage debtor continues to pay the agreed amortization (paying off the loan they took to eventually buy the property outright), then these 'lay-offs' (a bookmakers' term for reducing their exposure to potential large pay-offs) remain hidden i.e. they depend on a rising market to conceal 'match-fixing'.

And of course this is all built on the illusion of a perpetually rising market. When - who could have predicted - the market falls, and simultaneously mortgage debtors can no longer keep up the agreed amortization payments, a process called foreclosure is instituted whereby the physical asset (land or property) is reclaimed by the current owner of title. This is done in order to sell off the asset to recover as much of the debt as possible. So far so good.

But in order to foreclose, ownership of title must be legally established. If the mortgage debt has been subdivided and that bets on that debt have been resold - it becomes very difficult to establish who actually has title.

The fraud emerges in companies trying bypass title. The law is relatively simple = who has the bearer deeds has the title, and thus owns the debt. The scramble now is to establish title - by other means.